You've seen them but not noticed them. You've heard them but not listened to them.

The new documentary "20 Feet From Stardom" shines a spotlight away from center stage over to the world of female backup singers.

Directed by Morgan Neville, the film looks most specifically at the lives and careers of six women — Darlene Love, Merry Clayton, Lisa Fischer, Táta Vega, Claudia Lennear and Judith Hill — who span generations of music and have worked with a broad spectrum of artists including the Rolling Stones, Michael Jackson, Phil Spector, Stevie Wonder, Sting and Ike and Tina Turner.

Playing now in Los Angeles and New York and beginning to expand around the country this weekend, "20 Feet" premiered on the opening night of the Sundance Film Festival just like last year's "Searching for Sugar Man," another tale of music trumping obscurity that went on to win the Oscar for documentary. Audiences have burst into applause during showings of "20 Feet From Stardom," moved by the excitement of the music and the emotions of the story.

The movie has also helped to push its subjects further into the spotlight many of them have never before seen. Hill, recently a contestant on "The Voice," performed a song from the film on "The Tonight Show." Love was interviewed for the first time on "Late Show" after singing there for many years. A "Best of Merry Clayton" is being released. Lennear is looking to get a new band together.

"To make a film about a group of people that maybe didn't have the opportunities and catch every break they should have, and then have that film provide those opportunities is something I could never have allowed myself to imagine happening," said Neville. "But it is actually happening, and that's the biggest reward."

The film was the idea of Gil Friesen, former president of A&M Records and executive producer of films such as "The Breakfast Club" and "Better Off Dead." While at a Leonard Cohen show, he was struck by the background singers and realized their world had never been explored.

Having never produced a documentary before, Friesen came to Neville, a longtime director and producer of such music-related docs as the Carole King/James Taylor film "Troubadours" and the Rolling Stones bio "Crossfire Hurricane."

"When I said, 'Backup singers are interesting but what's the film going to be?' he said, 'I have no idea; that's your job.' It was really unchartered territory," Neville said of their initial conversation.

Neville and Friesen interviewed dozens of background singers as they shaped the story. From there, Neville wrote up a treatment of what he thought the rest of the film could be. Though he was initially concerned the film would be a downbeat look at failure to achieve, in the perseverance of his subjects Neville found something more.

"The breakthrough to me was that the film is not about trying to go solo and trying to achieve your dreams and not making it," said Neville. "It's about the third act of the film, what happens when you don't achieve your dreams and how the measure of a person is how they dealt with that. That's the deeper thing to me."

Neville said that Lennear was perhaps the most difficult subject for him to find. Though she had enjoyed relative fame while a member of the Ikettes with Ike and Tina Turner, later releasing a solo album in 1973 and appearing in the 1974 film "Thunderbolt and Lightfoot," Lennear left the music business in the early 1980s to become an educator.

"I had just kind of dropped off the face of the earth, but this movie has allowed many of us to resurface," Lennear said. "What's really curious about it is that all of us went through the same sort of things, we all shared so many experiences that we didn't know we were sharing at the time. But now we're finding out, 'Wow, that happened to me too.' I have learned a lot from the movie."

For Hill, youngest of the film's subjects and a one-time backup singer with Michael Jackson who is trying to step into a solo career of her own, learning the way her story echoes the stories of those before her has been encouraging.

"It just shows me that it's OK to make mistakes, it's OK to fail. You can get back up again and you're stronger," Hill said. "The power of the women in the film and how they've overcome hardship is inspiring. Realizing in my life, even when things don't turn out the way you want, you're on your path."

The success of "20 Feet From Stardom" has been tempered by the fact that Friesen died in December from leukemia. He had seen the finished film and knew that it was premiering at Sundance, but his absence made the experience bittersweet.

"As great as this whole thing has been, I still can't believe that he's not here," Neville said. "It's cool, but it would have been so much better if he was here."